Photographic emulsions containing delta-polycarbonyl sensitizers



United States Patent C) PHOTOGRAPHIC EMULSIONS CONTAINING DELTA-POLYCARBQNYL SENSETIZERS Burton D. Wilson and Thomas F. Murray, Rochester, N.Y., assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Filed May 29, 1961, Ser. No. 113,066

it t Ciaims. (Cl. 596-407) This invention concerns photographic silver halide emulsions, and more particularly, photographic silver halide emulsions containing novel sensitizing materials,

It is well known in the photographic art that silver halide emulsions can be chemically sensitized with a variety 'of materials in order to increase the speed thereof. Certain chemical sensitizers are believed to react with the silver halide to form on the surface of the silver halide minute amounts of silver sulfide, silver, or other noble metals. In addition, other classesof compounds can be utilized to increase the sensitivity of photographic silver halide emulsions that apparently do not enter into chemical combination with the silver halide.

mamas Patented Aug. .17, 1965 ice bon atoms containing an aryl substituent), heterocyclic radicals (typically nitrogen-containing radicals having It is an object of this invention to provide novel photo- It is still another object'of this invention to provide novel photographic silver halide emulsions containing a new class of carbonyl-containing sensitizers.

..It is likewise an object of this invention to provide novel photographic elements having coated thereon silver halide emulsions containing new chemical sensitizers.

These and other objects of the invention are accomplished by incorporating into a photographic silver halide emulsion a sensitizing amount of certain delta-polycarbonyl compounds of the type described hereinafter.

The sensitizer addenda of the invention are delta-polycarbonyl compounds having the following structure:

R16 1'1 (3 R CHOHOH R R wherein R and R are hydrogen atoms, acyl radicals wherein R is an alkyl radical, such acyl radicals as acetoacetyl etc.), or carbamoyl radicals including primary, secondary and tertiary carbarnoyl radi: cals); wherein R and R are alkyl radicals, alkoxy radicals or hydrazino (NHNH radicals; and wherein R c is a hydrogen atom or an alkyl radical; The carbamoyl radicals for the substituents Randi? can represent a wide variety of radicals including radicals having the structure wherein R and R are hydrogen atoms, alkyl radicals, aryl radicals (including aryl radicals substituted with, halogen atoms, alkyl, alkoxy, carboxy, alkali metal sulfonic acid salts and the like groups), cycloalkyl radicals (typically having 4 to 9 carbon atoms), aralkyl radicals (typically an alkyl radical having 1 to 6 car- 4 to 6 carbon atoms such as piperidyl, pyridyl, pyrimidyl and the like), carbon and hydrogen atoms which together with the nitrogen atom form a heterocyclic ring (typically containing4 to 6 carbon atoms such as a pyrr olidine, a piperidine, a pyridinium, or a pyridine ring), and amino groups to form as carbohydrazide radical O c i NnNn2) The alkyl radicals referred to above generally have 1 to 20 carbon atoms and preferably are lower alkyl radicals having 1 to 6 carbon atoms. Preferably the subject sensitizers are symmetrical compounds, to wit, the substituents R and R are the same and the substituents R and R are the same, although we also contemplate the utilization of unsymmetrical compounds having the above generic formula as sensitizers in the photographic emulsions of the invention. Polymers formed by extending the polymer chain through substituents R and R or R and R also improve the sensitivity of photographic silver halide emulsions.

The sensitizing addenda of the invention can be added to photographic silverhalide emulsions for the purpose of increasing the sensitivity or speed thereof.

The preparation of photographic silver halide emulsions such as are suitably sensitized with the addenda of the invention typically involves three separate operations: (1) emulsification and digestion of silver halide, (2) the freeing of the emulsion of excess water-soluble salts, suitably by washing with water, and (3) the second digestion of after-ripening to obtain increased emulsion speed or sensitivity. (Mees; The Theory of the Photographic Process, 1954.) The sensitizers: of our invention can be added to the emulsion before the final digestion or after-ripening, or they can be added immediately prior to the coating.

The particular quantity of the present sensitizers used in a given emulsion can vary, depending upon the ef fects desired, degree of ripening, silver content of the emulsion, etc. The amount used is also dependent upon the particular stage at which the sensitizer is added during the preparation of the emulsion. We have found that generally from about .1 to IOYgrams per mole of silver halide are quite adequate to accomplishthe desired sensitization. Exposure of the treated emulsion in conventional photographic testing apparatus, such as in intensity scale sensitometer, will reveal the most advantageous concentrations forthe present sensitizers in that particular emulsion. Such techniques are well understood by those skilled in the art. n

The sensitizeriaddenda of the invention. can be added to photographic emulsions using any of the well-known techniques in emulsion making. For example, the subject sensitizers can be dissolved in a suitable solvent and added to the silver halide emulsion, or they can be added to the emulsion in the form of a dispersion similar to the technique used to incorporate certain types of colorforming compounds (couplers) in a photographic emulsion. Techniques of this type are described in Jelley et al. US. Patent 2,322,027, issued June 15, 1943, and Fierke et al. US. Patent 2,801,171, issued July 30, 1957 The solvent should beselected so that it hasno harmful The sensitizer addenda of the invention can be used in various kinds of photographic emulsions. In addition to being useful in orthochro'matic, panchromatic, and infrared sensitive emulsions, they are also useful in X-ray and other non-optically sensitized emulsions. They can be added to the emulsion before or after any optical sensitizing dyes which may be used. Various silver salts can be used as the sensitive salt such as silver bromide, solver iodide, silver chloride, or mixed silver halides such as silver chlorobromide or silver bromoiodide. The subject addenda can be used in emulsions intended for color photography, for example, emulsions containing color-forming couplers or emulsions to be developed by solutions containing couplers or other color-generating materials, emulsions of the mixed-packet type, such as described in Godowsky U.S. Patent 2,698,794, issued January 4, 1955,,or emulsions of the mixed grain type, such as described in Carroll and Hanson U.S. Patent 2,592,243, issued April 8, 1952. The subject sensitizers can also be used in emulsions which form latent images predominantly on the surface of the silver halide crystal or in emulsions which form latent images predominantly inside the silver halide crystal, such as those described in Davey and Knott U.S. Patent 2,592,250, issued April 8,

The photographic silver halide emulsions'of the invention can-contain the addenda commonly utilized in photographic silver halide emulsions including other speed-increasing sensitizers than those of the invention, optical sensitizers, plasticizers, stabilizers, gelatine hardeners,

coating aids and the like. 1

In the preparation of the silver halide dispersions employed for preparing silver halide emulsions, there can be employed as the dispersing agent for the silver halide in its preparation, gelatin or some other colloidal material such as colloidal albumin, a cellulose derivative, or a synthetic resin, for instance, a polyvinyl compound, although gelatine is'preferred. Some'colloids which can be used are polyvinyl alcohol or a hydrolyzed polyvinyl acetate as described in Lowe U.S. Patent 2,286,215, issued June 16, 1942; a far hydrolyzed cellulose ester such as cellulose acetate hydrolyzed to an acetyl content of 1-9-26% described in U.S. Patent 2,327,808 of Lowe and Clark, issued August 24, 1943; a water-soluble ethanolamine cellulose acetate as described in Yutzy U.S. Patent 2,322,085, issued June 15, 1943; a polyacrylamide having a combined acrylamide content of 30-60% and a specific viscosity of 0.251.5 on an imidized polyacrylamide of like acrylamide content and viscosity as described in Lowe, Minsk and Kenyon U.S. Patent 2,541,474, issued February 13, 1951; zein as described in Lowe U.S. Patent 2,563,791, issued August 7, 1951; a vinyl alcohol polymer containing urethane carboxylic acid groups of the type described in Unruh and Smith U.S. Patent 2,768,154, issued October 23, 1956; or containing cyano-acetyl. groups such as the vinyl alcohol-vinyl cyanoacetate copolymer as described in Unruh, Smith and Priest U.S. Patent 2,808,331, issued October 1, 1957; or a polymeric material which results from polymerizing a protein or a saturated acylated protein with a monomer having a vinyl group as described in Illingsworth, Dann and Gates U.S. Patent 2,852,382, issued September 19,

1958. If desired, compatible mixtures of two or more of these colloids can be employed for dispersing the silver halide in its preparation.

The above-described emulsions of the invention can be coated on a wide variety of supports in accordance with usual practice. Typical supports for photographic elements of the invention include cellulose nitrate film, cellulose acetate film, polyvinyl acetal film, polystyrene film, polyethyleneterephthalate film and related films of resinous materials, as well as glass, paper, metals and others.

The inventionis further illustrated by the following examples of preferred embodiments thereof.

A high speed gelatino-silver halide emulsion panchromatically sensitized with a cyanine dye was prepared. The silver halide was composed of 6 mole percent of silver iodide and 94 mole percent of silver bromide. The emulsion comprised 245 g. of gelatin per mole of silver halide. Several sensitizers were incorporated in varying amounts in the prepared photographic emulsion. The emulsion containing the various sensitize-rs and control emulsions containing no sensitizer were coated on cellulose acetate film supports at coverages of 430 mg. of silver per square foot. Sample strips of the resulting photographic elements were exposed in the usual manner in an Eastman Type Ib Sensitometer, then developed for five minutes at 68 F., and then fixed, washed and dried in the usual manner. The developer had the following Water to make one liter.

The results of the sensitometric tests are summarized by the data set out in the table below. The amount of addenda is designated as grams of addenda per mole of .silver halide.

TABLE Example Conc., Relative Number Sensitizer Addenda g./mole Speed Gamma Fog of AgX 1 Control 1.17 0.11 3,5-diaeetyl-2,6-hep- 0. 3 132 1. 20 11 tanedione. do 3.0 200 1. 23 21 2 Control 100 1. 32. 12 Diethyl methylene- 0. 3 126 1. 35 l2 bisacetoacctate.

d 170 1. 47 14 182 1. 38 15 100 1. 22 l4 Dimethyl 1nethyleuc- 0. 3 162 1. 25 14 bisaeetoacetate.

178 1. 23 16 195 1. 15 17 100 1. 2O 10 Diethyl a,v.-diacetyl- 0.3 120 1. 18 .12

firncthylglutarate. do 138 1.17 11 170 1. 15 12 100 1. 22 11 Dietliyl methylene- 0. 3 126 1. 33 l2 bispropionylacctate. do 3.0 123 1.47 .13 6 Control 100 1. 38 11 Methylenebisaeeto- 0. 3 110 1. 28 11 acotanilide.

145 1. 45 12 141 1. 28 14 100 1. 13 15 Methylenebis-a-aceto- 0. 3 1. l5 12 acetamidopyridine.

141 1. 47 13 151 1. 48 14 100 1. 25 10 Methylencbi 3. O 115 1. 02 11 acct-o-anisidide). 9 Control 100 1. 25 l0 Methylenebis-(aceto- 0. 3 100 1. 20 11 acetFo-toluidide).

d 105 1. 13 12 120 1. 03 12. 100 1. 17 12 4,6-dipr0pionyl-3,7- 0. 3 100 1. 22 15 nonanedione.

118 1. 18 14 123 1. l8 15 100 1. 13 l4 Methylencbis(dimeth- 0. 3 141 1. 17 14 yl-3-oxoglutarate) do 0.9 166 1.15 .15 0 3.0 178 1.12 .21 12 Control 100 1. 13 l4 Ethy idenebis-(di- 0.3 132 1. 20 13 methy1-3-oxoglutarate). do 3. 0 138 1.17 .14 13 Control 100 1. 22 13 Diethyl mothylene- -0. 3 1. 23 14 bismalonamate.

Relative Sensitizer Addenda Speed Gamma Control 100 1. 13 12 y( 107 1. 25 12 methoxy-Z-butunone).

----.do 115 1.17 .11 ControL 100 1. 13 12 Poly(1,3-dicarbo- 107 1, 2g 11 methoxy-z-butar none).

H-110 110 1. 25 11 Control 100 1. 13 12 ye y .a- 115 1. 27 12 diacetylglutarate) do 118 1.35 .12 Control" 100 1. 13 12 Methylenebism ,N- 115 1. 23 12 diethylacetoacetamide).

do 106 1.18 .13 Control.... 100 1 1. 22 11 Methylenebis(N- 129 1. 23 11 eyelohexylacetoacetamide). -.do 141 1.30 11 138 1. 23 11 100 1. 15 11 107 1. 20 10 Control 100 1. 10 11 Methylenebis(N ,N- 195 1. 15 13 dimethylaeetoaeetamide).

do u 200 1.13 19 ControL. 100 1.10 11 Methylenebis(aceto- 159 1. 12 11 aeetopiperidide). 1

Control 100 1.10 11 Methylenebislaceto 141 1. 12

acetc-lfl-pheuethyl- 1 e am 1 166 1. O3 100 1. 08 263 0.95

methylpyridinium p-tosylate) Control 100 1. O8 Methylenebisaceto- 178 1. 13

acetarnide.

.do 191 1.15 Control 100 1. 28 2,6-heptanedione 107 1. 40

do 118 1. 40 Control 100 1. 12 3-acetyl-2,0Heptane- 219 1. 05

I230 234 1.05 Control 100 1.08 Isopropylidgne-blste 110 1. 15

120 1.10 Control- 100 1. 25 Methylenebis-malon- 110 1. 32

hydrazide. Control 100 1. 12 Methylenebis(N- 186 1. 08

ethylacetoaeet; amide).

d0 186 1.12 Control 100 1. 12 Methylenebis(p- 129 1. 13

fluorgacetoaeete d 1 141 1.12 15 100 1. 12 13 178 1. l7 19 3. 251 1: 182 1. 0s .22 Control 100 1. 12 13 Methylenebis(N- 118 1. 12 14 metlahylacetoacetnff ddf u 159 1.02 .16 Control 100 1.12 13 Methylenebis(3,4.5- 110 1. 12 15 trimettiociiryaceto- .n ft i i fuui 132 1.10 Control 100 1. 12 Methylenebis(p- 110 1. 12

carbgxyacetoacet- 132 1. 15 .14 Control 100 1. 12 13 Methylenebis(p-sul- 126 1. 13 13 ioacegoacetariitlide) i 111 sa "521 8."? 141 1.17 ..do 159 1.18

The sensitizer compounds were prepared by condensation of the proper reactive methylene compound with an aldehyde, in solution, but without an added catalyst as described in the examples below which correspond in number to the numbered examples set out in the table, unless otherwise indicated.

Example 1.-3,5-diacetyl-2,o-hepmnedione A solution of 200 g. of 2,4-pentanedione and ml. of 37 percent aqueous formalin in 100 ml. of absolute ethanol was allowed to stand at room temperature for three days. It was then poured into water and extracted with benzene. The residue remaining after removal of solvent was vacuum distilled, B.P. 1l5130 C./0.0S mm., 12 1.4678. The yield was 126 g. (59.4 percent) of a colorless, viscous liquid, which when cooled and seeded (from a previously prepared sample), crystallized to a solid mass. Several recrystallizations from ether gave colorless crystals, M.P. 41-42" C. (corn).

Analysis.-Calcd. for C H O C, 62.25; H, 7.60; M.W., 212. Found: C, 62.6; H, 7.7; M.W., 202 (ebulloscopic, in benzene). 1

Example 2.Diethyl melhylenebisacetoacetaie This compound was prepared by a procedure of Rabe described in Annalen, 332, 10 (1904),. in which the (acidic) impurities in the ethyl acetoacetate and the formalin are the only catalytic agents present. A solution of 260 g. of ethyl acetoacetate and 75 ml. of 37 percent aqueous formalin in 70 ml. of absolute ethanol was allowed to stand at room temperature for 50-60 hours. It was then poured into water and extracted with benzene.- The slightly colored residue remaining after removal of the solvent (average: 232 g. percent), n 1.450) could be vacuum distilled, but extensive decomposition occurred. The distillation was improved using an oil diffusion pump, and improved still more by molecular distillation. The product was a colorless liquid, B.P. 0/5 1, 11 1.450-1.455.

AnaIysis.-Calcd. for C I-1 0 C, 57.34; H, 7.40; M.W., 272. Found: C, 57.7; H, 7.5; M.W., 298 (ebulloscopic, in benzene).

Example 3.-Dimezhyl methylenebisacetoacezate Example 4.Diethyl a,a'-diacetyl-fl-methylglumrate This compound was prepared by the procedure of Example 2, replacing the formalin by 56 ml. of anhydrous acetaldehyde, and allowing the reaction to run for six days. After removal of solvent there was left a residue of 208 g. Distillation at aspirator pressure yielded ca. g. of recovered ethyl acetoacetate. The pot residue (ca. 40 g.) was distilled under high vacuum to give a small quantity (ca. 3 g.) of the desired product, 131?. till-95 C./0. 080.l0 mm., 11 1.453.

Analysis.-Calcd. for C I-1 0 C, 58.73; H, 7.74. Found: C, 59.8, 59.2, 59.7; H, 7.8, 7.8, 7.3.

7 Example 5.Diethyl methylenebis(propionylacetate) This compound Was prepared by the procedure of EX- ample 2, replacing the acetoacetate by 57.7 g. of ethyl propionylacetate and scaling down the other reactant quantities by a factor of 2.5. The oily residue on removal of solvent weighed 57.4 g. Distillation at 20 i7 mm. gave a 37 g. recovery of starting ester. Continued distillation at high vacuum gave 14.6 g. (66.7 percent, based on unrecovered starting material) of a colorless liquid, B.P. 0 C./0.05 mm., 11 1450-1452. The infrared spectrum resembled those of Examples 3 and 4. Analysis.-Calcd. for C I-1 0 C, 59.98; H, 8.06. Found: C, 60.6, 60.8; H, 8.2, 7.8.

Example 6.Methyleaebis(acetoacetanilide) A mixture of 125 g. of acetoacetanilide and 27 ml. of 37 percent aqueous formalin were mixed in 300 ml. of absolute ethanol and stirred until all the solids had gone into solution (30 minutes). The solution was allowed to stand for 66 hours, towards the end of which time precipitation of solid occurred, which was removed by filtration and dried, wt. 116 g. (90.0 percent). Several recrystallizations from alcohol gave colorless crystals, M.P. 193 C. (dec.) (corr).

Analysis.Calcd. for C H N O C, 68.84; H, 6.05; N, 7.64. Found: C, 69.0; H, 6.3; N, 7.8.

Example 7.Methylenebis(ix-acetoacetamid0pyridine) Using a procedure similar to that of Example 6, 35.6

V g. of a-acetoacetamidopyridine and 7.0 ml. of 37 percent aqueous formalin were mixed with 700 ml. of absolute ethanol and kept at 0 C. for 24 hours, then 24 hours at room temperature, followed by isolation. Yield: 30.8 g. (83.7 percent). Several recrystallizations from aqueous ethanol gave colorless crystals, M.P. 132-l33 C. (dec.) (corr).

Analysis.-Calcd. for C H N O C, 61.95; H, 5.47; N, 15.21. Found: C, 61.8; H, 5.5; N, 15.0.

Example 8.-Metlzylenebis o-acetoacetanisidide) Example 9.Methylenebis(0-acet0acet0t0luidide) Using a procedure similar to that of Example 6, a

slurry of 102 g. of o-acetoacetotoluidide and 19 ml. of 37 percent aqueous formalin in 250 ml. of absolute ethanol was stirred intermittently for hours, followed by isolation of the solids. Yield: 93.0 g. (88.6 percent). Several recrystallizations from such ethanol gave colorless crystals, M.P. 192 C. (dec.) (corr).

Analysis.Calcd. for C H N O C, 70.03; H, 6.64; N, 7.10. Found: C, 69.8; H, 7.0; N, 7.2.

Example 10.-4,6-dipropi0nyl-3,7-n0naaedi0ne A solution of 64.1 g. of 3,5-heptanedione in 40 ml. of absolute ethanol was cooled to 0 C. and 18 ml. of 37 percent aqueous formalin was added. The solution was then cooled to 10 C. and 15 drops of piperidine was added. The mixture was kept at 10 to 15 C. for

48 hours with occasional shaking. A solid started precipitating after about 25 hours. This solid (6.2 g.) was iilteredotf and recrystallized from alcohol. It proved to be 4,6-dipropionyl-3ethyl-3-hydroxy-2-rnethylcyclohexanone, M.P. 138-139 C. (corr), the cyclic aldol product from 4,6-dipropionyl-3,7-nonanedione. The filtrate above was poured into 500 ml. of water and extracted repeatedly with benzene. Removal of the solvent left 59.0 g. of aviscous oil which partially crystallized when seeded with the aldol product. This solid (14.7 g.) was removed by filtration. The filtrate was then distilled to give about 25 g. of product as a thick, slightly easiest a 0 yellowish oil, B.P. 115l18 C./0.02 mm, n 1.4664- Analysis.-Calcd. for C H O C, 67.14; H, 9.01. Found: C, 67.5; H, 9.4.

Example 1 1.-Methylenebis(dimethyl 3 -0x0gl uzarate) A solution of 34.8 g. of freshly distilled dimethyl 3- oxoglutarate and 14 ml. of 37 percent aqueous formalin in 50 ml. of methanol was allowed to stand at room temperature for 97 hours. The colorless crystals which formed were filtered off and washed well with methanol. Yield: 10.0 g. (27.8 percent), M.P. 157-158 /2" C. (corr). Decomposition appeared to occur on recrystallization (probably due to formation of the corresponding pyran).

Analysis.-Calcd. for O l-1 0 C, 50.00; H, 5.60. Found: C, 50.0; H, 5.8.

Example 1 2 .Ethylidenebis( dimethyl 3-0x0glatarate) By a procedure similar to Example 11, a solution of 34.8 g. of freshly distilled dimethyl 3-oxoglutarate and 11.5 ml. of acetaldehyde in 30 ml. of methanol was allowed to stand at room temperature for 97 hours. Isolation of the solids gave 3.13 g. (8.4 percent) of colorless crystals, M.P. l71-172 C. (corr). Decomposition occurred as before.

Analysis-Calm. for C H O C, 51.34; H, 5.92. Found: C, 51.6; H, 5.9.

Example 13.-Diethyl methylenebismalonamate A solution of 32.8 g. of ethyl malonamate, 9.0 ml. of 37 percent aqueous formalin, and 1 ml. of diethylamine in 100 ml. of absolute ethanol was heated under reflux for seven hours, then allowed to stand at room temperature overnight, and poured into water. The aqueous solution was extracted repeatedly with benzene and then concentrated to dryness under vacuum. The residue crystallized on standing. Yield: 10.1 g. (29.4 percent). Several recrystallizations from ethanol gave colorless crystals, M.P. ISO-152 C. (corr).

Analysis.Calcd. for C H N O C, 48.17; H, 6.62; N, 10.21. Found: C, 48.1; H, 6.4; N, 10.0.

Example J4.Methylenebis(acetoacezobeazylamide) Using a procedure similar to that of Example 6, 47.8 g.

' of acetoacetobenzylamide and 9.0 ml. of 37 percent aqueous formalin were mixed in 350 ml. of absolute ethanol and stirred until all the solids had dissolved (two hours). The solution was allowed to stand about hours, during which time precipitation of solid occurred, which was removed by filtration and dried. Yield: 36.8 g. (74.6 percent). Several recrystallizations from ethanol gave colorless crystals, M.P. 169 /2-170 /2" C. (corr). Analysis.-Calcd. for C H N O C, 70.03; H, 6.64; N, 7.10. Found: C, 69.2, 68.9; H, 6.4, 6.4; N, 7.2.

Example 15.-P0ly(1,S-dicarbomethoxy-Z-bataaone) A mixture of 34.8 g. of freshly distilled dimethyl 3- oxoglutarate and 14 ml. of 37 percent aqueous formalin was dissolved in ml. of absolute methanol. The solution was cooled to 10 C. and ten drops of piperidine was added. The mixture was stored at about 0 C. for one week. The upper phase was decanted off and the gummy solid remaining was taken up in dimethylformamide and precipitated by pouring into water. The crude solids (23.8 g.) were placed in a Soxhlet extractor and exhaustively extracted with ethanol. The ethanol extract when poured into water gave a gummy solid (3.2 55.), isolated by centrifugation. This solid was taken up in benzene and freeze-dried to give an amorphous powder. The residue from the extraction (20.6 g.) was purified further by repeated solution in dimethylformamide and precipitation by pouring into water. a Analysis.Calcd. for (C H O C, 51.61; H, 5.42. 15a. Found: C, 51.4; H,5.7; M.W. (ithermometr'ic) Example 16.-Ply(ethylene a,a-diacetylglutarate) Using a procedure similar to Example 2, 23.0 g. of ethylene bisacetoacetate and 7.0 ml. of 37 percent aqueous formalin, dissolved in 100 ml. of absolute ethanol, were allowed to stand at room temperature. After four days, phase separation occurred and addition of more ethanol would not make the mixture homogeneous. After the mixture had stood two weeks, the upper phase was decanted from the lower, oily layer. The polymer was purified by repeated solution in acetone and precipitation by pouring into water. The polymer was a viscous, slightly colored oil, exhibiting no tendency to solidify.

Analysis.-Calcd. for (C H O C, 54.54; H, 5.83. Found: C, 54.1; H, 5.9; M W. (thermometric) 950.

Example 17.Methylenebis(N,N-dimethylacetoacetamide) Using a procedure similar to Example 6, a solution of 44.3 g. of N,N-diethylacetoacetamide and ml. of 37 percent aqueous formalin in 25 ml. of absolute ethanol was allowed to stand at room temperature for 72 hours. Volatile materials were removed at mm. and the residue distilled using an oil diffusion pump to give about 23 g. of a viscous, slightly-colored oil, B.P. 144-15 1 C./8-10,a, n 1.4819.

AIzalysis.Cald. for C I-1 N 0 C, 62.55; H, 9.26; N, 8.58. Found: C, 62.6; H, 8.9; N, 8.7.

The methylenebisacetamides of Examples 18 through were prepared by the method of Example 6, substituting the proper acetoacetamide for acetoacetanilide, except as described.

Example 18.-Methylenebis(N-cyclohexylacetoacetamide) The crude material was recrystallized three times from ethanol, giving colorless crystals, M.P. 207 (dec.) (corr.).

Analysis.-Calcd. for C H N O C, 66.64; H, 9.05; N, 7.40. Found: C, 66.6; H, 9.3; N, 7.5.

Example 19.Methylenebis( a-pivaloylacelanilide) The crude material was recrystallized three times from 50 percent aqueous ethanol, giving colorless crystals, M.P. 161164 C. (corr.).

Analysis.Calcd. for C H N O C, 71.97; H, 7.61; N, 6.22. Found: C, 71.6; H, 7.2; N, 6.5.

Example 20.- Methylenebis(N,N-dim-ethylacet0acetamide) The crude material was distilled using an oil diifusion pump, B.P. 121-132" C./1416,u, 11. 1.4910. The

product is a viscous, yellow oil.

Analysis.Calcd. for C H N O r C, 57.76; H, 8.20; N, 10.36. Found: C, 57.6; H, 8.2; N, 8.7, 8.4.

Example 21 .Methylenebis(acetoacetopiperidide) The crude material was distilled using an oil difiusion pump, B.P. 130-442 C./2125,u, 11 1.5062. The product is a viscous, yellow oil.

Analysis.--Calcd. for C H N O C, 65.12; H, 8.63; N, 7.99. Found: C, 64.7; H, 8.7; N, 7.7.

Example 22.--Methylenebis(acetaaceto-p-phenethylamide) Example 23.-Methylenebis(u-acetoacetamido-N- methylpyridinz'um p-tosylate) The crude material was an amorphous, very hygroscopic, colorless solid. It eluded all attempts at purifis cation.

Analysis.--Calcd. for C H N S O C, 56.74; H, 5.44; N, 7.56; M .W., 740.9. Found: C, 55.7, 55.5; H, 5.6, 5.5; N, 7.3; M.W., 677.

Example 24.- -Methylenebisacetoacetamide The crude material was recrystallized three times from nitromethane, giving colorless crystals, M.P. 161.5-162 C. (dec.) (corr.).

Analysis.--Calcd. for C H N O C, 50.46; H, 6.59; N, 13.08. Found: C, 50.1; H, 6.5; N, 13.2.

Example 25.-2,6-heptanea'ione This compound was prepared by the procedure of Overberger et al. disclosed in J. Am. Chem. Soc., 74, 3290 (1952), from 99.6 percent pure 2,6-lutidine; M.P. 32.533.5 C. (corr.).

Example 26.3-acetyl-2,6-heptauedione This compound was prepared by the procedure of Lacey disclosed in J. Chem. Soc., 1625 (1960). The product was a colorless oil, B.P. 7275 C./0.02 mm, 11,, 1.4594.

Example 27.-Is0propylidenebistetron'ic acid This compound was prepared using the procedure of Wolff and Schimpff disclosed in Annalen', 315, 145 (1901), M.P. 200-202 C. (corr.).

Example 28.Methylenel$ismalonhydrazide Example 29.Methylenebis(N-ethylacetoacetamide) The crude material was recrystallized three times from ethanol, giving colorless crystals; M.P. 170.5-171.5 C. (corr.).

Analysis.-Calcd. for C H N 0 C, 57.76; H, 8.20; N, 10.36. Found: C, 57.4; H, 8.3; N, 10.6.

Example 30.-Methylenebis(p-fluoroacetoacetanilide) The crude material was recrystallized three times from ethanol, giving colorless crystal; M.P. 221-221.5 C. (corr.)l Analysis.--Calcd. for C H N F O C, 62.68; H, 5.01; N, 6.96. Found: C, 62.9; H, 5.2; N, 7.1.

Example 31.Methylenebis(N-n-butylacetoacetamide) The crude material was recrystallized four times from ethanol, giving colorless crystals; M.P. 138139 C. (corr.).

Analysis.-Calcd. for C H N O C, 62.55; H, 9.26; N, 8.58., Found: C, 62.6;H, 9.4; N, 8.5.

Example 32.Methylenebis (N-methylacetocetanilide) The crude material was distilled using an oil difiusion pump, giving a yellow, viscous oil; B.P. ca. 110 C./8p; n 1.554.

Analysis.-Calcd. for C H N O C, 70.03; H, 6.64; N, 7.10. Found: C, 70.1; H, N, 7.4.

, i1 y Example 33. Z .4ethylenebis(3,4,5-lrimethxylacetoacetanilide) The crude material was recrystallized four times from acetonitrile, giving lightly peach-colored crystals; MP. 1S6 l57 C. (corr.).

Analysis.--Calcd. for C H N O C, 59.33; H, 6.27; N,'5.13. Found: C; 59.0; H, 6.0; N, 5.0.

Exam pi e 34.-Metlzylenebis(p-carb oxyacetoacetanilide) The crude material was digested with boiling nitromethane to remove unreacted p-carboxyacetoacetanilide. The pale yellow residue could not be purified further.

I Analysis.Calod. for C H N O C, 60.79; H, 4.88; N, 6.16. Found: C, 60.3; H, 5.2; N, 6.0.

Example 35 Methylenebis(p-sulfoacetoacetanilide) disodium salt The crude material was recrystallized three times from 50 percent aqueous ethanol, giving colorless crystals; M.P. 300 C.

Analysis.--Calcd. for C H N S O Na C, H, 3.53; N, 4.91. Found: C, 43.8; H, 3.6; N, 4.6.

The invention thus provides a new and useful class of photographic sensitizers. The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected Within the spirit and scope of the invention described hereinabove and as defined in the appended claims.

We claim:

l. A photographicsilver halide emulsion. containing a sensitizing amount of a sensitizer having the formula:

0 O H R 0 R CR CHCHCH\ R R wherein R and R are selected from the group consisting of a hydrogen atom, an acyl radical and a carbamoyl radical; wherein R and R are selected from the group consisting of an alkyl radical, and alkoxy radical having the formula OR and wherein R is an alkyl radical and a hydrazino radical; and wherein R is selected from the group consisting of a hydrogen atom and an alkyl radical.

2. A photographic silver halide emulsion containing a sensitizing amount of a sensitizer having the formula wherein R is an alkyl radical and R is a carbamoyl radical.

3. A photographic silver halide emulsion containing a sensitizing amount of a sensitizer having the formula O O I] ll no CR o CHCHzCH 0 II \II no on wherein R is an alkyl radical. 4. A photographic silver halide emulsion containing a sensitizing amount, of a sensitizer having the formula wherein R is an aryl radical and R is an alkyl radical.

i2 5. A photographic silver halide emulsion containing a sensitizing amount of a sensitizer having the formula if n ROO\ /COR 0 OHCHzCH O 11/ RC CR wherein R is an alkyl radical.

6. A photographic gelatino-silver halide emulsion sensitized with a sensitizer having the formula H 5% R10 CR1 wherein R is an alkyl radical having 1 to 6 carbon atoms and wherein R is a carbamoyl radical having the formula i a BC on o oHomoH 0 \ll no on wherein R is an alkyl radical having 1 to 6 carbon atoms.

8. A photographic gelatino-silver halide emulsion sensitized with a sensitizer having the formula if Ii R!O\ /CR1 0 CHCHzCH 0 II/ \II RENO V CNHR wherein R is an aryl radical and R is an alkyl radical having 1 to 6 carbon atoms.

9. A photographic gelatino-silver halide emulsion sensitized with a sensitizer having the formula i it ROG /OOR o orrornon '0 II \II no CR wherein R is an alkyl radical having 1 to 6 carbon atoms.

10. A photographic gelatino-silver halide emulsion containingQl to 10 grams per mole of silver halide of 3,5- diacetyl-2,6-heptanedione.

11. A photographic gelatino-silver halide emulsion containing .1 to 10 grams per mole of silver halide of diethyl methylenebisacetoacetate.

12. A photographic gelatino-silver halide emulsion con taining .1 to 10 grams per mole of silver halide of dimethyl methylenebisacetoacetate.

13. A photographic gelatino-silvei' halide emulsion containing .l to 10 grams per mole of silver halide of 3- acetyl-2,6-heptanedione.

14; A photographic gelatino-silver halide emulsion containing .lto 10 grams per mole of silver halide of methylene-bis (N,N-dimethylacetoacetamide) 15. A photographic gelatino-silver halide emulsion containing .1 to 10 grams per mole of silver. halide of a sensitizer selected from the group consisting of 3,S-diacetyl-Z,6-heptanedione,

diethyl methylenebisacetoacetate, methylenebisacetoacetanilide,

diethyl mathylenebispropionylacetate, diethyl 61,0:-diacety1-,8-methylglutarate, dirnethyl methylenebisaceioacetate, methylenebis wacetoacetamidopyridine) methylenebis acetoacet-o-anisidicle methylenebis acetoacet-o-toluidide) 4,6-dipropionyl3,7-nonanedione, methylenebis (dimethyl-3-oxog1uarate) ethylidenebis (dimethyl-3oxoglutarate diethylmethylenebismalonarnate, methylnebis (N-benzylacetoacetamide) methylenebis (N,N-diethylacetoacetamide) methylenebismalonhydrazide,

methylenebis (N-cyclohexylacetoacetamide methylenebis a-pivaloylacetanilide) 2,6-heptanedione, 3-acetyl-2,6-heptanedione,

methylenebis (N,N-dimethylacetoacetamide methylenebis (acetoacet-fl-phenethylamide) methylenebis (acetoacetopiperidide), methylbenebis (a-aceto acetamido-N-niethylpyridinium p-tosylate) methylenebisacetoacetamide, methylenebis (N-ethylacetoacetamide) methylenebis (p-fluoroacetoacetanilide) methylenebis (N-n-butylacetoacetamide) methylenebis N-methylacetoacetanilide methylenebis 3-4,-5-trime1hy0xyacetoacetianilide) methylenebis (p-carboxyacetoacetanilide and methylenebis (p-sulfoacetoacetanilide disodium salt.

References Cited by the Examiner UNITED STATES PATENTS NORMAN G. TORCHIN, Primary Examiner.

PHILEP E. MANGAN, Examiner. 

1. A PHOTOGRAPHIC SILVER HALIDE EMULSION CONTAINING A SENSITIZING AMOUNT OF A SENSITIZER HAVING THE FORMULA: 